The present invention relates to navigation systems and in particular to computer-enhanced navigation system that can provide maneuvering instructions for a user of the navigation system.
Computer-based navigation systems for use on land have become available in a variety of forms and provide for a variety of useful features. One exemplary type of navigation system uses (1) a detailed data set of one or more geographic areas or regions, (2) a navigation application program, (3) appropriate computer hardware, such as a microprocessor, memory, and storage, and, optionally, (4) a positioning system. The detailed geographic data set portion of the navigation system is in the form of one or more detailed, organized data files or databases. The detailed geographic data set may include information about the positions of roads and intersections in or related to one or more specific geographic regional areas, and may also include information about one-way streets, turn restrictions, street addresses, alternative routes, hotels, restaurants, museums, stadiums, offices, automobile dealerships, auto repair shops, etc.
The positioning system may employ any of several well-known technologies to determine or approximate one's physical location in a geographic regional area. For example, the positioning system may employ a GPS-type system (global positioning system), a "dead reckoning"-type system, or combinations of these, or other systems, all of which are well-known in the art.
The navigation application program portion of the navigation system is a software program that uses the detailed geographic data set and the positioning system (when employed). The navigation application program may provide the user with a graphical display (e.g. a "map") of the user's specific location in the geographic area. In addition, the navigation application program may also provide the user with specific directions to locations in the geographic area from wherever the user is located.
Some navigation systems combine the navigation application program, geographic data set, and optionally, the positioning system into a single unit. Such single unit systems can be installed in vehicles or carried by persons. Alternatively, navigation application programs and geographic datasets may be provided as software products that are sold or licensed to users to load in their own personal computers. In further alternatives, the navigation system may be centrally or regionally located and accessible to multiple users on an "as needed" basis, or alternatively, on-line via a network or communications link. Personal computer-based systems may be stand-alone systems or may utilize a communication link to a central or regional or distributed system. Also, users may access a navigation system over an on-line service such as the Internet, or over private dial-up services, such as CompuServe, Prodigy, and America Online. In-vehicle navigation systems may use wireless communication connections. Navigation systems may also be used by operators of vehicle fleets such as trucking companies, package delivery services, and so on. Navigation systems may also be used by entities concerned with traffic control or traffic monitoring.
Computer-based navigation systems hold the promise of providing high levels of navigation assistance to users. Navigation systems can provide instructions for traveling to desired destinations, thereby reducing travel times and expenses. Navigation systems also can provide enhanced navigation features such as helping commuters and travelers avoid construction delays and finding the quickest routes to desired destinations. Navigation systems can also be used to incorporate real-time traffic information.
One of the features that can be provided by navigation systems is maneuver guidance. For example, after a navigation system determines a suitable route that can be used to travel from a starting location to a destination location, it would be desirable to provide the user with easy-to-understand instructions --visual, auditory or both visual and auditory--to guide the user. These instructions may take the form of a series of driving maneuvers needed to follow the calculated route. These driving maneuvers may be provided all at once, or preferably may be provided one at a time as the vehicle in which the navigation system is installed is being driven along the calculated route. The maneuver instructions may be provided somewhat in advance of when the maneuver is required in order to prepare the driver for the maneuver. For example, a driving maneuver may consist of an audio message that states "Continue in left lane for one quarter mile and exit onto the ramp to Interstate 290."
Accordingly, there is a need in navigation systems to provide a user with clear, unambiguous, and consistent instructions. Further, it is important in navigation systems to determine a series of maneuver instructions quickly in order to have them ready for a user-driver when needed.
Therefore, it is an objective to provide an improved navigation application maneuver generation feature that provides clear, unambiguous, and consistent instructions quickly and in an efficient manner.